### [CVE-2018-18397](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-18397)
![](https://img.shields.io/static/v1?label=Product&message=n%2Fa&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=n%2Fa&color=blue)
![](https://img.shields.io/static/v1?label=Vulnerability&message=n%2Fa&color=brighgreen)

### Description

The userfaultfd implementation in the Linux kernel before 4.19.7 mishandles access control for certain UFFDIO_ ioctl calls, as demonstrated by allowing local users to write data into holes in a tmpfs file (if the user has read-only access to that file, and that file contains holes), related to fs/userfaultfd.c and mm/userfaultfd.c.

### POC

#### Reference
- https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.7
- https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.7
- https://usn.ubuntu.com/3901-1/
- https://usn.ubuntu.com/3901-1/

#### Github
- https://github.com/ARPSyndicate/cvemon